Aortic stenosis is a disease that affects over sixteen million individuals over the age of sixty-five in the United States alone, and is characterized by a narrowing of the aortic valve in the heart, resulting in an obstruction to normal blood flow. In normal operation, leaflets of the aortic valve allow or restrict blood flow based on their respective open and closed states. That is, and generally, in such open state, the leaflets of a healthy aortic valve open wide, and in such closed state, the leaflets of a healthy aortic valve close at least substantially completely along with the beating of a person's heart. Contrastingly, the leaflets of a diseased, open aortic valve do not open as wide as those of a healthy, open aortic valve, and the leaflets of the diseased, closed aortic valve may not close sufficiently. A diseased aortic valve thus obstructs blood flow and poses significant health risks.
The standard treatment for severe aortic stenosis is open-heart surgery to replace the effected aortic valve with a prosthetic, mechanical valve. However, this procedure is not an option for high-risk, inoperable patients, and so alternative treatments often must be considered. The primary alternative to the aforesaid open-heart surgical procedure is transcatheter aortic valve replacement (commonly and hereinafter referred to as “TAVR”), a minimally invasive procedure that delivers a prosthetic valve through the patient's arteries, thereby obviating the opening of the patient's chest. In a typical TAVR procedure, a relatively small incision is made in the patient's groin in order to give the doctor access to a major artery that leads to the aorta. The physician thereafter inserts a guide wire within the incision to send a catheter and a replacement, prosthetic aortic valve through the aorta to the patient's heart. To position this replacement valve, physicians generally use florescent dye with real time fluoroscopy in conjunction with an ultrasound probe placed in the patient's esophagus.
Using known TAVR positioning technologies, physicians rely on two-dimensional imagery to determine the correct position at which to place the prosthetic aortic valve. While somewhat effective, this method introduces a degree of uncertainty in the replacement valve positioning procedure, which results in a misplacement rate of as much as ten percent (according to the PARTNER II Clinical Trials). Aortic valve misplacement, in turn, often results in significant paravalvular leak (i.e., leakage of blood around such valve), thereby necessitating the placement of a second such valve within the first such replacement valve. Furthermore, not only is it estimated that up to ten percent of prosthetic valves are misplaced through TAVR procedures, but it is also estimated that two and a half percent of all TAVR procedures require revision. The placement of a second valve results in additional radiation exposure, contrast dye exposure, and anesthesia exposure, each of which individually and in combination creates an increased risk for further health complications, such as kidney damage or failure.
Thus, while existing alternatives to open-heart surgery exist for treating aortic stenosis, various drawbacks, including those mentioned above, remain. Consequently, there exists a need to position a prosthetic valve quickly, accurately, and without revision, and, towards that end, there exists a need for technology that provides physicians with a more accurate, quantitative method for determining the correct position at which to deploy or place a prosthetic aortic valve during a TAVR procedure.